The invention relates to end cutting milling tools and methods of using them to mill concave surfaces.
An end cutting milling tool is rotated about a cutting axis and has a cutting end and has cutting blades at the cutting end and along the flank for removing material from a workpiece contacted by the blades. In one mode of operation the tool, the cutting axis is maintained generally perpendicular to a desired surface on the workpiece, and the tool is moved generally transversely to the cutting axis across the workpiece while the tool is rotating about its axis to remove material. Flat end cutting milling tools have flat bottoms at the cutting ends. These tools often make a small angle between the cutting axis and vectors normal to the desired surface of the workpiece so that cutting occurs at an edge of the cutting end. Another type of end cutting milling tool is a ball end milling tool, which has a hemispherical cutting end; i.e., the radius at the cutting end is one-half the tool diameter at the cutting end. End cutting milling tools are provided with a variety of blades or other cutting surface components. Examples of end cutting milling tools and methods of their use are described in U.S. Pat. Nos. 4,850,761; 4,662,117; and 4,104,943. Such tools can also cut by having the flank portions contact the workpiece.